fix: prevent asset conflicts between React and Grid.js versions

Add coexistence checks to all enqueue methods to prevent loading
both React and Grid.js assets simultaneously.

Changes:
- ReactAdmin.php: Only enqueue React assets when ?react=1
- Init.php: Skip Grid.js when React active on admin pages
- Form.php, Coupon.php, Access.php: Restore classic assets when ?react=0
- Customer.php, Product.php, License.php: Add coexistence checks

Now the toggle between Classic and React versions works correctly.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

node_modules/framer-motion/dist/es/value/use-motion-value.mjs

@@ -0,0 +1,38 @@
+import { useContext, useState, useEffect } from 'react';
+import { motionValue } from './index.mjs';
+import { MotionConfigContext } from '../context/MotionConfigContext.mjs';
+import { useConstant } from '../utils/use-constant.mjs';
+
+/**
+ * Creates a `MotionValue` to track the state and velocity of a value.
+ *
+ * Usually, these are created automatically. For advanced use-cases, like use with `useTransform`, you can create `MotionValue`s externally and pass them into the animated component via the `style` prop.
+ *
+ * ```jsx
+ * export const MyComponent = () => {
+ *   const scale = useMotionValue(1)
+ *
+ *   return <motion.div style={{ scale }} />
+ * }
+ * ```
+ *
+ * @param initial - The initial state.
+ *
+ * @public
+ */
+function useMotionValue(initial) {
+    const value = useConstant(() => motionValue(initial));
+    /**
+     * If this motion value is being used in static mode, like on
+     * the Framer canvas, force components to rerender when the motion
+     * value is updated.
+     */
+    const { isStatic } = useContext(MotionConfigContext);
+    if (isStatic) {
+        const [, setLatest] = useState(initial);
+        useEffect(() => value.on("change", setLatest), []);
+    }
+    return value;
+}
+
+export { useMotionValue };